It is known in the field of machining to use tangential cutting inserts, i.e. cutting inserts having a cutting face and a flank face disposed transversally to the cutting face, where a hole for clamping the cutting insert to a machining tool is arranged through the flank face. A known advantage of such a tangential cutting insert is that the width of the cutting face may be reduced without reducing the length of the cutting insert so that the bulkiness of the cutting face may be also reduced—especially when mounted onto a rotating machining tool, for instance a milling tool. In this way, since the bulkiness of the cutting face is reduced, it enables to design rotating machining tool having reduced diameter. Another advantage is that the tangential cutting insert is oriented in such a manner that during a cutting operation on a workpiece the cutting forces are directed along a major (thicker) dimension of the cutting insert, whereby the cutting insert can withstand greater cutting forces than when oriented in such a manner that the cutting forces are directed along a minor (thinner) dimension of the cutting insert.
EP-A-0 769 341 discloses a milling tool comprising tangential cutting inserts vertically and horizontally arranged onto the milling tool for machining a work piece transversally and along a rotating axis of the milling tool. The tangential cutting inserts disclosed in this document comprise a cutting face having a substantially rectangular shape. The cutting face further has quarter-circle-shaped transition cutting edge portions between each straight cutting edge portions of the cutting face. Furthermore, the horizontal and vertical tangential cutting inserts are arranged onto the milling tool such that, if the position of the cutting edge of a horizontal and a vertical cutting inserts relative to the rotating axis of the milling tool are gathered in a same plane, an end portion of each cutting edges are superimposed on each other. In this way, continuity of the machining operation between each successive cutting inserts is preserved.
However, one drawback of this known milling tool (particularly in short-chipping materials such as cast-iron) is that the machined surface generated by the milling tool may be subjected to frittering at locations where the tangential cutting inserts exit the work piece during milling. The milling tool may hereby also exhibit detrimental vibrations during milling. This result in a machined surface with an inappropriate surface finish notably subjected to mechanical behaviour issues, cracking or visual defects.